Brush for electrical machines



Aug. 4, 1925. 1,548,466

F. HETTINGER BRUSH FOR ELECTRICAL MACHINES Filed June 22, 1921 11vVENTOR /4 ZwL/v 8 ILA? TOkIVEYS Patented Ans". l- TEES.

UNITED STATES PATENT orrics.

FEED HETTINGER, OF RUTHERFORD, NEW (TIER-E3131", ASSIG-NOB, TO CHAS. E.CI-IAPIN n 60., A CORPORATION OF NEW YORK.

BRUSH, FQB, ELECTRICAL MACHINES.

Application filed June 22, 1921. Serial No. erases.

T 0 all to 710m it may concern Be it known that I, Finn) Hnrrnvenn, acitizen of the United States, residing at Rutherford, N. J, haveinvented certain new and useful improvements in Brushes] for ElectricalMachines, of which the following is a clear, full, and exactdescription.

This invention relates to brushes for use in dynamos, motors and otherelectrical machines and to processes of making the same.

In one of the most common forms of brushes for electrical machines, thebrushes are made of wire gauze folded and compressed into the desiredshape to form a brush. In order to hold the commutator engaging ends ofthe wires of brushes of this character in place and prevent them fromdigging into or scratching the commutator, a lubricating metal, such aslead, is commonly applied to the brush in a molten condition and allowedto harden upon the same. Brushes of this type heretofore produced havehad the lubricating metal applied to the brush so as to leave certaininterstices in the body of the brush and often there are certain partsof the gauze of which the brush is composed contacting with the commutator, which are not covered with the lubricating metal. Thus, in theprior brush constructions, the lubricating material is not alwayseffective in preventing the scratchingof the commutator and particles ofthe wires of the gauze are often dislodged by the engagement of thecommutator with the brush, and enter the bearings of the commutatorshaft, thereby causing a great deal of trouble. This latter diflicultyhas induced the use of solid metal brushes to a considerable extent,although such brushes are far more expensive than wire gauze brushes andin certain respects do not give as good results. in addition to theapplication of lubricating metal, such as lead, to the gauze, the end ofthe brush is often dipped in solder to hold the brush together.

Une object ofthe present invention is to produce a brush of thewiregauze type in which a lubricating metal is applied to the wires in anovel and improved manner, so as to prevent more effectively the diggingof the wires into the commutator and the dis lodgement of smallparticles of wires from the brush and also so as to hold the brushtogether in a reliable manner. l/Vith this ob ject in view, a feature ofthe present invention consists in a brush having a lubricating metalapplied to the wires so as to fill entirely the interstices between thesame and form in connection with the wires a solid block. ,Theapplication of the lubricating metal to the wires in this mannerincreases the effectiveness of the metal in holding the wires in placeat the point at which they engage the commutator 'and also enables thelubricating metal to lubricate more thoroughly the point of contact ofthe brush with the commutator.

Another feature of the present invention consists in a brush, the bodyof which is formed of wire gauze and which has a solid or unbrokenmetallic layer on the exterior thereof, the surface of which is smoothand even, and which consists chiefly at least of the metal of which thewire gauze is formed. With a brush having a solid metallic layer of thischaracter, there is practically no liability that small particles of thebrush will become dislodged therefrom when the brush is in use, and theexterior of the brush will have substantially the same char acter andappearance as that of a solid metal brush made of the metal of which thegauze is formed.

Certain other features of the invention relate to the method employed informing the solid exterior surface of the brush.

The invention also involves certain other novel and improved featureshereinafter described and particularly pointed out in the claims, theadvantages of which will be read ily understood and appreciated by thoseskilled in the art.

The invention will be readily understood from the accompanying drawingsillustrating a brush embodying the invention in its preferred form andalso illustrating certain steps in the process which is preferablyfollowed in making the brush, taken in connection with the followingdetailed description of the brush and the process of making the same Inthe drawings, Fig. 1 is a perspective view of a strip of wire gauzewound into a flattened roll preparatory to forming a brush therefromFig. 2 is a perspective view of the roll of gauze after compression intothe desired shape to form a brush g nseaeee Fig. 3 is a perspective viewillustrating the manner in which the lubricating metal is applied to thebrushes;

Fig. l is a perspective view of a brush a tier the lubricating metal hasbeen applied thereto;

Fig. 5 is a perspective view illustrating the manner in which theexterior oi? the brush is finished after the application of thelubricating metal to the brush; and

Fig. 6 is a perspective view of a completed brush.

In making a brush in accordance with the present invention as preferablycarried out, relatively narrow strip of wire screen or gauze made ofcopper, brass or other metallic wire and preferably cut on the bias, iswound into a roll such as that indicated at 2, Fig. 1, which may beeither cylindrical in term or may be somewhat flattened, as shown insaid figure, depending upon the shape which the brush is to have aftercompression. The roll of gauze is then subjected to a heavy pressure tocompress the same into the desired brush form. Fig. 2 of the drawingillustrates the roll after compression to form a brush, indicated at t,of prismatic shape.

After the roll of gauze has been compressed into the desired shape, thelubricating or anti-friction metal is applied to the compressed blockthus termed in such a manner to coat all of the surfaces ot the wiresand to form in connection with said wires a solid block. The lubricatingmetal may be advantageously applied to the brush by immersing the brushin a bath ol this metal in a molten condition. In order to clean thesurfaces of the wires of which the block is made and to provide asuitable flux for the lubricating metal, the block is first dipped orsoaked in a suitable soldering solution. The block is then taken fromthe soldering solution and deposited in a bath consisting of thelubricating metal. Preterably the lubricating metal em )loyed isrelatively soft as con'ipared with the metal cl which the wires of thebrush are termed and should such as to have a relatively high degree ofelectrical conductivity and to give the proper lubricating cti cct. Purelead has been found in practice to give highly satieitactory resultsalthough other metals or alloys having the proper qualities may be usedin a molten condition. The block is soaked in this bath of molten metallong enough to allow the metal to penetrate all the interstices in theblock and to cover the surfaces of all of the wires of which the blockis formed. As illustrated in Fig. 3, the brushes l are immersed in atank 6 containing a bath of the lubricating metal indicated at 8 in amolten condition. After having been soaked for asur'licient length oitime in the metal bath, the block is removed from the bath and allowedto cool so that the lubricating metal hardens and forms in connectionwith the wires ot the block, a solid metallic block, all of thelubricating metal being allowed to be retained within the body of theblock. Fig. 4; shows one of the brushes after it has been removed fromthe bath at the lubricating metal and the metal has been allowed toharden thereon, the brush being indicated by the reference numeral 9.

illrtter the application. of the lubricating metal to the brush, thebrush is preferably formed with a substantially solid metallic layer onthe outside thereof, the outer surface at which is smooth and even, saidlayer consisting principally at least of the metal of which the wires ofthe brush are formed. The brush may be easily and cheaply pro vided withsuch a metallic layer by subjecting the exterior of the brush after theap plication of the lubricating metal thereto to the-action of apolishingor abrading device. Fig. 5 of the drawings illustrates a seriesof? the blocks resting on a table 10 and being subjected to the actionof a grinding or abrading wheel 12. During the abrading operation themetal of which the wires of the brush are composed is swaged and spread.over the exterior surface 01? the brush, thereby giving the brush asolid metallic exterior layer having a smooth even surface and composedalmost entirely of this metal. When the brush is made of copper wiregauze, for example, the brush. alter the abrading operation will havesubstantially the appearance of a solid copper brush. Fig. 6 sh( vs abrush after the exterior thereof has been subjected to the action of anabrading device to form a layer of metal of the character described onthe exterior of the brush, the brush being indicated by referencenumeral 14-.

Brushes may be made in accordance with the present process with verylittle, if any, addition to the cost oil. manufacture as compared withan ordinary brush of the wire gauze ype and may be made much morecheaply than a solid metallic brush. On account of the manner in whichthe lulu'icating material is applied to and retained in the lillld'l,there is no necessity of dipping the brush in a soldering solutioi'i tohold the same together.

It is to be understood that the invention is not limited to theparticular brush con struction or to the particular process of makingthe same illustrated and des ribed in the present application, but thatthe invention may be embodied in brushes ot di'l'titerent constructionsand that the process may be varied from that described within the scopeof the claims.

Having explained the nature and object of the invention and havingspecifically described a form in which the invention is preferablyapplied, what is claimed is:

1. A brush for electrical machines, comprising a series of conductingwires, and lubricating metal filling all of the interstices between thewires and forming in connection with said wires a solid block. I

2. A brush for electrical machines comprising a series of layers of wiregauze compressed into block form, and lubricating metal filling theinterstices between the wires of the same layer and between the wires ofadjacent layers to form a solid block.

A brush for electrical machines, comprising a coil of Wire gauzecompressed into block fornnand lubricating metal filling the intersticesbetween the wires of said block and forming in connection with saidwires a solid block.

4. A brush for electrical machines, comprising wire gauze formed into ablock and lubricating metal entirely filling the interstices between thewires of said block to form a solid block.

5. A brush for electrical machines comprising a section of wire gauzefolded and compressed into a block and a lubricating metal filling theinterstices between the wires of said block, said block having a smoothsurfaced substantially solid metallic exterior layer principallycomposed of the metal of which said wires are formed.

6. A brush for electrical machines, comprising a section of wire gauzefolded and compressed into a block the body of which is provided with asmooth surfaced substantially solid metallic exterior layer.

7. A brush for electrical machines comprising a section of wire gauzefolded and compressed into a block and having a smooth surfacedsubstantially solid metallic exterior layer composed chiefly of themetal of which said wires are formed.

8. A brush for electrical machines comprising a section of wire gauzefolded and compressed into block form and having the wires on theexterior thereof flattened and smoothed oil and the points between saidwires filled in with metal composed chiefly at least of the. material ofwhich said wires are formed to form a substantially smooth exteriorsurface.

9. A brush for electrical machines comprising a section of wire gauzemade into block form and having the wires on the exterior thereofflattened and smoothed ofl and the points between said wires filled inwith metal composed chiefly at least of the material of which said wiresare formed to form a substantially smooth exterior surface.

10. A brush for electrical machines, the body of which is formed of wiregauze and having its outer part abraded to form a smooth surfacedsubstantially solid metallic exterior composed principally of the metalof which the wire gauze is formed.

11. The process of making a brush for electrical machines, whichcomprises folding a strip of wire gauze and compressing the same to forma block, treating the block with a soldering solution, soaking the blockin a bath of pure molten lead and then abrading the exterior of theblock to give the same a smooth exterior surface.

12. The process of making a) brush for electrical machines, whichcomprises folding a strip of wire gauze and compressing the same to forma block, and abrading the exterior of the block to give the same asmooth exterior surface.

13. A process of making a brush for elec trical machines which comprisesas a step, abrading the exterior of a wire screen block so as to form asmooth surfaced, substantially solid exterior layer composed principallyof the metal of which the screen is formed.

lt. A process 'of making a brush for electrical machines which includesas a step, applying a lubricating material to a wire screen block so asto fill entirely the interstices between the wires of the screen andform in connection with said wires a solid block.

15. A brush for electrical machines comprising a wire gauze foundationand lubrieating metal entirely filling the interstices between the wiresof said gauze to form a solid metallic block.

16. A brush for electrical machines comprising a series of 'rouped wiresarranged in brush form and compressed into a block and having its outerpart abraded. to form a smooth surfaced substantially solid metal licexterior layer.

Signed at Rutherford, N. J. this 17th day of June, 1921.

MR. FRED I-lETTlNGEl-t. l/Vitnesses M. GIRHER, FRANK B. MOREHEAD.

